Friday, 2 March 2018

Weather report Summer 2017-18

My version of Summer is based on biology on the Southern Tablelands of NSW rather than astronomy (if that is the correct term for solstices and equinoxes) and starts on 1 November and finishes on the last day of February. So here is a summary of those 4 months.

Overall: a reasonably moist period, balancing a wet first two months with a dry second two) with low Maxima (thank you November) and high Minima.

Item

Units

2017-18

Average

Start year of average

Rainfall

mm

262.4

300.4

2007

Maximum temperature

oC

27.4

28.5

2010

Minimum temperature

oC

12.0

11.1

2010

1500Hrs Humidity

%

42.3

39.7

2013

Looking at those 4 attributes in more detail.

Rainfall

I have a series of observations back to 1985, but my usual reports in this blog use my own series going back to 2007. I have shown both here.

This Summer was still one of the drier ones in recent times particularly in comparison with the very wet Summers of 2010-11-12. It was still an improvement over 2016/17.

Temperatures

The next chart shows the average summer Minima and Maxima since 2010, avoiding the possible data quality issues with some maxima in the noughties. The monthly contributions ending up with a moderate maximum and elevated minimum come in the next sections.

Maximum temperatures

Basically November was relatively cool while the other three months were very close to average.

Minimum temperatures

I restricted this section to the years since 2010 in this report (the monthly reports cover all years back to 1993) to compare with the discussion of maximum temperatures above, although there don't seem to be the same quality issues for the minimums. That becomes important since the comparison with recent years shows February 2018 to be slightly below average whereas the long view shows it, like most other recent months to be above average.

The graphs shows the other three months to be well above the average since 2010.

Humidity

An interesting chart with the first two months much more humid than average and the second two being much drier than average. In my monthly report for February I comment on the very dry days encountered in that month.